Technical Manual

East Wind Technologies, Inc.

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3.4.13 About KEY Identifier

There is a byte of KEY identifier in command of MIFARE 1K/4K cards. This byte will

identify the way to get the card key.

KeyIdentifier

BIT7

BIT6

BIT5

BIT4

BIT3

BIT2

BIT1

BIT0

BIT0 = 0: KEY A; authenticate Key A of the card.

BIT0 = 1: KEY B; authenticate Key B of the card.

BIT1 = 0: Using the following 6 bytes Key in command.

BIT1 = 1: Using the downloaded Key by command.

BIT6:BIT5:BIT4:BIT3:BIT2: Index of the Key already downloaded (0 to 31).

BIT7=0: The block need to authenticate with the above key.

BIT7=1: The block has been authenticated. This operation do not need to authenticate again

(this operation and automatic detecting card could not be used at the same time).

If BIT1 is 0, then these 5 bits (BIT6 to BIT2) are unused. If BIT1 is 1, then use the already

downloaded key. Users need to download key(s) first; and then the 6 bytes key in the command

are left unused, but the 6-byte is necessary in the command sequence.

E.g.: key Identifier is 0x00; binary system is 0

0000000, here:

BIT0 = 0; authenticate Key A of the card

BIT1 = 0; using the key in command

BIT6:BIT5:BIT4:BIT3:BIT2:

00000, because not use the already downloaded key, the index

key is useless in this command.

E.g.: key Identifier is 0x33; binary system is 0

0110011, here:

BIT0 = 1; authenticate Key B of the card

BIT1 = 1; using the downloaded Key in the module

BIT6:BIT5:BIT4:BIT3:BIT2:01100, then use the already downloaded key 01100, and

hexadecimal is 0x0C, decimal is 12.